[TriLUG] how do USB disks and USB wifi cards work?

[David Brain]

Hi,

Not quite - the 'drive like' behavior of USB devices is a standard
(http://en.wikipedia.org/wiki/USB_mass_storage_device_class) so the
kernel code just has to know how to talk that to make USB disks work.

I do not believe there is a similar standard for 'network like
devices' (which would be nice...).  So for a USB network device you
are in the normal situation of needing to have a, normally
vendor/chipset specific driver.

David.

On Mon, Jun 9, 2008 at 11:30 AM, Joseph Mack NA3T <jmack at wm7d.net> wrote:
> I have assumed that a USB disk worked something like this
>
> o the USB driver arranged for the USB transport hardware to
> deliver whatever was at the end of the USB cable to the OS.
> The OS saw a disk and loaded the disk driver code. The OS
> talked to the disk without knowing (or maybe not caring)
> that an intermediate layer was carrying the bits back and
> forth to the disk.
>
> This was fine till I wondered if a USB wifi card worked the
> same way. I assume that the manufacturers use their standard
> wifi hardware and instead of using a PCI or pcmcia
> interface, they put in a usb interface. Presumably then the
> standard Linux usb code would handle the usb link, and the
> OS would use the standard wifi driver for that piece of wifi
> hardware.
>
> However I went to the madwifi webpage to find that they
> don't support USB wifi cards (because of difficulties
> writing the code). Presumably my model of how USB connected
> devices work is wrong.
>
> Anyone fill me in?
>
> Thanks Joe
>
> --
> Joseph Mack NA3T EME(B,D), FM05lw North Carolina
> jmack (at) wm7d (dot) net - azimuthal equidistant map
> generator at http://www.wm7d.net/azproj.shtml
> Homepage http://www.austintek.com/ It's GNU/Linux!
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